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<div class="title">src/ca/uqac/dim/turtledb/Projection.java</div>  </div>
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<a href="_projection_8java.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/*-------------------------------------------------------------------------</span>
<a name="l00002"></a>00002 <span class="comment">    Simple distributed database engine</span>
<a name="l00003"></a>00003 <span class="comment">    Copyright (C) 2012  Sylvain Hallé</span>
<a name="l00004"></a>00004 <span class="comment"></span>
<a name="l00005"></a>00005 <span class="comment">    This program is free software: you can redistribute it and/or modify</span>
<a name="l00006"></a>00006 <span class="comment">    it under the terms of the GNU General Public License as published by</span>
<a name="l00007"></a>00007 <span class="comment">    the Free Software Foundation, either version 3 of the License, or</span>
<a name="l00008"></a>00008 <span class="comment">    (at your option) any later version.</span>
<a name="l00009"></a>00009 <span class="comment"></span>
<a name="l00010"></a>00010 <span class="comment">    This program is distributed in the hope that it will be useful,</span>
<a name="l00011"></a>00011 <span class="comment">    but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<a name="l00012"></a>00012 <span class="comment">    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the</span>
<a name="l00013"></a>00013 <span class="comment">    GNU General Public License for more details.</span>
<a name="l00014"></a>00014 <span class="comment"></span>
<a name="l00015"></a>00015 <span class="comment">    You should have received a copy of the GNU General Public License</span>
<a name="l00016"></a>00016 <span class="comment">    along with this program.  If not, see &lt;http://www.gnu.org/licenses/&gt;.</span>
<a name="l00017"></a>00017 <span class="comment"> -------------------------------------------------------------------------*/</span>
<a name="l00018"></a>00018 <span class="keyword">package </span>ca.uqac.dim.turtledb;
<a name="l00019"></a>00019 
<a name="l00020"></a>00020 <span class="keyword">import</span> java.util.*;
<a name="l00021"></a>00021 
<a name="l00022"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html">00022</a> <span class="keyword">public</span> <span class="keyword">class </span><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html">Projection</a> <span class="keyword">extends</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_unary_relation.html">UnaryRelation</a>
<a name="l00023"></a>00023 {
<a name="l00024"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#ac0b060433dea772e5c6c5965fa3668ad">00024</a>   <span class="keyword">protected</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_schema.html">Schema</a> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#ac0b060433dea772e5c6c5965fa3668ad">m_schema</a>;
<a name="l00025"></a>00025   
<a name="l00026"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a60f1d608b522ff25ef5a897766ec76a2">00026</a>   <span class="keyword">public</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a60f1d608b522ff25ef5a897766ec76a2">Projection</a>(<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_schema.html">Schema</a> sch, <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_relation.html">Relation</a> rel)
<a name="l00027"></a>00027   {
<a name="l00028"></a>00028     super();
<a name="l00029"></a>00029     <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#ac0b060433dea772e5c6c5965fa3668ad">m_schema</a> = sch;
<a name="l00030"></a>00030     <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_unary_relation.html#a1ae5d140ec09a2db41d6ff8cd7c0f81c">m_relation</a> = rel;
<a name="l00031"></a>00031   }
<a name="l00032"></a>00032 
<a name="l00033"></a>00033   @Override
<a name="l00034"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a7b72d8d38df297c3a77a13ef2c4491d3">00034</a>   <span class="keyword">public</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_schema.html">Schema</a> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a7b72d8d38df297c3a77a13ef2c4491d3">getSchema</a>()
<a name="l00035"></a>00035   {
<a name="l00036"></a>00036     <span class="keywordflow">return</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#ac0b060433dea772e5c6c5965fa3668ad">m_schema</a>;
<a name="l00037"></a>00037   }
<a name="l00038"></a>00038   
<a name="l00044"></a>00044   <span class="keyword">private</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_tuple.html">Tuple</a> project(<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_tuple.html">Tuple</a> t)
<a name="l00045"></a>00045   {
<a name="l00046"></a>00046     <span class="keywordflow">if</span> (t == null)
<a name="l00047"></a>00047       <span class="keywordflow">return</span> null;
<a name="l00048"></a>00048     <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_value.html">Value</a>[] parts = <span class="keyword">new</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_value.html">Value</a>[<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#ac0b060433dea772e5c6c5965fa3668ad">m_schema</a>.size()];
<a name="l00049"></a>00049     <span class="keywordtype">int</span> i = 0;
<a name="l00050"></a>00050     <span class="keywordflow">for</span> (<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_attribute.html">Attribute</a> a : <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#ac0b060433dea772e5c6c5965fa3668ad">m_schema</a>)
<a name="l00051"></a>00051     {
<a name="l00052"></a>00052       parts[i++] = t.<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_tuple.html#a8d2822b5abbaf7d7e8f9e0ccd5a035db">get</a>(a);
<a name="l00053"></a>00053     }
<a name="l00054"></a>00054     <span class="keywordflow">return</span> <span class="keyword">new</span> Tuple(m_schema, parts);
<a name="l00055"></a>00055   }
<a name="l00056"></a>00056   
<a name="l00057"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a249d4253a8508fe10b740efefd01640b">00057</a>   <span class="keyword">public</span> <span class="keywordtype">void</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a249d4253a8508fe10b740efefd01640b">setSchema</a>(<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_schema.html">Schema</a> sch)
<a name="l00058"></a>00058   {
<a name="l00059"></a>00059     assert sch != null;
<a name="l00060"></a>00060     m_schema = sch;
<a name="l00061"></a>00061   }
<a name="l00062"></a>00062 
<a name="l00063"></a>00063   @Override
<a name="l00064"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#af0c6d79d648c715f55c8e24a88fddb43">00064</a>   <span class="keyword">public</span> <span class="keywordtype">void</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#af0c6d79d648c715f55c8e24a88fddb43">accept</a>(<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_query_visitor.html">QueryVisitor</a> v) <span class="keywordflow">throws</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_empty_query_visitor.html">EmptyQueryVisitor</a>.VisitorException 
<a name="l00065"></a>00065   {
<a name="l00066"></a>00066     <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_unary_relation.html#a1ae5d140ec09a2db41d6ff8cd7c0f81c">m_relation</a>.<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_relation.html#adb708409ab8c4a428ed102c4ce850ffe">accept</a>(v);
<a name="l00067"></a>00067     v.visit(<span class="keyword">this</span>);
<a name="l00068"></a>00068   }
<a name="l00069"></a>00069   
<a name="l00070"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_stream_iterator.html">00070</a>   <span class="keyword">protected</span> <span class="keyword">class </span><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_stream_iterator.html">ProjectionStreamIterator</a> <span class="keyword">extends</span> UnaryRelationStreamIterator
<a name="l00071"></a>00071   {
<a name="l00072"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_stream_iterator.html#a47cd73b7436c6d7efb5bfb716bd53559">00072</a>     <span class="keyword">public</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_stream_iterator.html#a47cd73b7436c6d7efb5bfb716bd53559">ProjectionStreamIterator</a>()
<a name="l00073"></a>00073     {
<a name="l00074"></a>00074       super();
<a name="l00075"></a>00075       m_outputTuples = <span class="keyword">new</span> LinkedList&lt;Tuple&gt;();
<a name="l00076"></a>00076     }
<a name="l00077"></a>00077     
<a name="l00078"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_stream_iterator.html#a24383741a67305404706bd85d871e7f6">00078</a>     <span class="keyword">protected</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_tuple.html">Tuple</a> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_stream_iterator.html#a24383741a67305404706bd85d871e7f6">internalNext</a>()
<a name="l00079"></a>00079     {
<a name="l00080"></a>00080       <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_tuple.html">Tuple</a> t = m_childIterator.next();
<a name="l00081"></a>00081       <span class="keywordflow">return</span> project(t);    
<a name="l00082"></a>00082     }
<a name="l00083"></a>00083   }
<a name="l00084"></a>00084   
<a name="l00085"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_cache_iterator.html">00085</a>   <span class="keyword">protected</span> <span class="keyword">class </span><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_cache_iterator.html">ProjectionCacheIterator</a> <span class="keyword">extends</span> UnaryRelationCacheIterator
<a name="l00086"></a>00086   {
<a name="l00087"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_cache_iterator.html#a4e716270767e236d22c891195887d79c">00087</a>     <span class="keyword">public</span> <span class="keywordtype">void</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_cache_iterator.html#a4e716270767e236d22c891195887d79c">getIntermediateResult</a>()
<a name="l00088"></a>00088     {
<a name="l00089"></a>00089       <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_table.html">Table</a> tab_out = <span class="keyword">new</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_table.html">Table</a>(<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a7b72d8d38df297c3a77a13ef2c4491d3">getSchema</a>());
<a name="l00090"></a>00090       super.getIntermediateResult();
<a name="l00091"></a>00091       Iterator&lt;Tuple&gt; it = m_intermediateResult.tupleIterator();
<a name="l00092"></a>00092       <span class="keywordflow">while</span> (it.hasNext())
<a name="l00093"></a>00093       {
<a name="l00094"></a>00094         <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_tuple.html">Tuple</a> t = it.next();
<a name="l00095"></a>00095         <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_tuple.html">Tuple</a> t2 = project(t);
<a name="l00096"></a>00096         tab_out.<a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_table.html#ac72d81075238b6f6e8406714a12156ff">put</a>(t2);
<a name="l00097"></a>00097       }
<a name="l00098"></a>00098       m_intermediateResult = tab_out;
<a name="l00099"></a>00099     }
<a name="l00100"></a>00100   }
<a name="l00101"></a>00101 
<a name="l00102"></a>00102   @Override
<a name="l00103"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a3a8c6185ea6febcc1b25375b65549982">00103</a>   <span class="keyword">public</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_relation_stream_iterator.html">RelationStreamIterator</a> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a3a8c6185ea6febcc1b25375b65549982">streamIterator</a>()
<a name="l00104"></a>00104   {
<a name="l00105"></a>00105     <span class="keywordflow">return</span> <span class="keyword">new</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_stream_iterator.html">ProjectionStreamIterator</a>();
<a name="l00106"></a>00106   }
<a name="l00107"></a>00107 
<a name="l00108"></a>00108   @Override
<a name="l00109"></a><a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a683984304a172b4a43b1bdd7aa752071">00109</a>   <span class="keyword">public</span> <a class="code" href="interfaceca_1_1uqac_1_1dim_1_1turtledb_1_1_relation_iterator.html">RelationIterator</a> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection.html#a683984304a172b4a43b1bdd7aa752071">cacheIterator</a>()
<a name="l00110"></a>00110   {
<a name="l00111"></a>00111     <span class="keywordflow">return</span> <span class="keyword">new</span> <a class="code" href="classca_1_1uqac_1_1dim_1_1turtledb_1_1_projection_1_1_projection_cache_iterator.html">ProjectionCacheIterator</a>();
<a name="l00112"></a>00112   }
<a name="l00113"></a>00113 
<a name="l00114"></a>00114 }
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